Hematology Review

Report
CR
Hematology
RBCs Disorders
Anemias
&Others
WBCs Disorders
Benign & Malignant
Hematological
Disorders
Hemostatic
Disorders
Introduction
• Blood consists of 55% plasma and 45%
formed elements.
• Formed elements include erythrocytes,
leukocytes, and thrombocytes.
Erythrocytes
• Normal range 4.0-5.0
million per mm3 in
adults.
• Biconcave shape.
• Diameter 7 microns.
• Cells for transport
of O2 and CO2.
• Life span 120 days.
Leukocytes
• Normal range 4 11 thousand per
mm3 in adults.
• Five types.
• Size 8-20 microns.
• Involved in fighting
infection,
combating allergic
reactions, and
immune
responses.
Thrombocytes
• Smallest cells in
the blood.
• Normal range
150,000-400,000.
• Active role in
coagulation and
hemostasis.
RBC
Disorders
Anemia
• Defined by measurement of hemoglobin
concentration.
• Manifestations (symptoms) are related to
duration and severity of anemia
– Body has physiologic responses to chronic
anemia such that many patients are
asymptomatic until hg < 8 g/dl .
– Fatigue, pallor, dyspnea, dizziness and
dyspnea on exertion
Signs
•
•
•
•
Pallor of mucous membranes (conjunctiva,
tongue, palm of the hands).
Nails are delicate and break easily.
Hair is thin.
Rough skin.
Classifications of Anemias
Microcytic, Hypochromic
Microcytosis – small cells (MCV <80)
– Iron deficiency
– Sideroblastic
– Anemia of chronic disease
– Lead poisoning
– Thalassemia trait
Microcytic, Hypochromic
• Many RBCs
smaller than
nucleus of normal
lymphocytes,
increased central
pallor.
Classifications of Anemias
Normochromic
– Hereditary Spherocytosis
– PNH
– G6PD deficiency
– Aplastic anemia
– Acute blood loss
Classifications of Anemias
Macrocytic
– Vitamin B12 deficiency
– Folate deficiency
– Liver disease
– Drugs
– MPD
Macrocytic RBCs
• Most RBCs larger
than nucleus of
normal
lymphocytes.
• increased MCV.
Macrocytic Anemia
 Macrocytosis – large cells (MCV >100)
 Check vitamin B12, RBC folate (why?), fasting
homocysteine, and methylmalonic acid (MMA)
*HC and MMA are elevated in subclinical B12 and
folate deficiency
IRON DEFICIENCY ANAEMIA.
 Iron deficiency is the most common
cause of anemia in every common
country of the world, and it is the most
important
cause
of
microcytic
hypochromic anaemia.
Nutritional and metabolic aspects of
the iron:
 Iron in the body is about 2.5-3 g.
 Iron in the Haemoglobin of the RBC
represents a greatest percent of body
constitutes.
 Iron presents in the body in two forms:
- Ferrittin.
- Haemosiderin.
Causes of iron deficiency anaemia:
1. Chronic blood loss, especially
gastrointestinal tract.
2. Increased demands, during
pregnancy, infancy, growth, lactation
and menstruated women.
3. Malabsorption especially in the cases
of gastroectomy and peptic ulcer.
4. Poor diet.
Clinical features:
1. When IDA is developing, the RE stores
(hemosiderin
and
ferritin)
become
completely depleted before anemia occurs.
2. At an early stage, no clinical abnormalities.
3. Later, patient may develops general
symptoms and signs of anemia.
4. Spoon or ridged nails in severe case of IDA.
5. Dysphagia.
Laboratory findings:
•Red cell indices:
Low Hb conc.
MCV, MCH, MCHC* 
•Blood film:
Hypochromic microcytic Picture.
Occasional Target cells.
Pencil shaped poikilocytes.
Normal reticulocyte count.
•Bone marrow iron:
Normal to hypercellular.
RBC precursors are increased in number.
Iron stain negative.
•Chemical testing on serum:
Serum iron
Decreased
Transferrin/TIBC
Normal to High
Serum ferritin
Decreased (Very low)
DD. Of microcytic anemia
Sideroblastic
anemias
Characterized by
Increase in total body iron
Presence of ringed sideroblasts in bone marrow
Hypochromic anemia.
Classification
• Hereditary form
• Acquired form (more common)
• Idiopathic – Refractory anemia with ringed
sideroblasts(RARS)
• secondery
Pathophysiology
• Disturbances of enzymes regulating heme
synthesis
• Ringed sideroblasts form when nonferritin
iron accumulated in the mitochondria that
circle the normoblast nucleus
Hereditary Sideroblastic Anemia
• Most common form is sex-linked and due
to
an
abnormal
aminolevulinate
synthetase enzyme (ALAS)
• Decreased heme synthesis due to block
in iron utilization perceived by body as
increased need for iron associated with
increased iron absorption results in iron
overload
Acquired Sideroblastic Anemia
 Idiopathic
RARS– acquired stem cell disorder
 Secondary
• Lead poisoning (plumbism)
 Inhibits cellular enzymes involved in heme
synthesis
• Malignancy
Laboratory findings in SA –
Peripheral Blood
•
•
•
•
Moderate to severe anemia
Target cells
Basophilic stippling
↑Fe, N to ↓TIBC, ↑% saturation, ↑ ferritin
• Bone marrow:
-Erythroid hyperplasia
-Ringed sideroblasts in more than 15% of
normoblasts.
**Lower number of ringed sideroblast in variety of
hematological disorders.
Macrocytic anemia
Macrocytic anemia
• Other causes include:
– Drug toxicity
– Hypothyroidism
– Liver disease
– Myelodysplasia
– MPO
Megaloblastic macrocytosis
• The smear in a patient with macrocytic anemia is
helpful in identification of megaloblastic changes
– macrocytes and hypersegmented neutrophils
(>5 lobes)
• DD: B12 deficiency, folate deficiency, drugs that
cause abn.DNA synthesis or folate metabolism,
liver disease and myelodysplastic syndromes
• Non-megaloblastic macrocytosis, on smear
patients may have large target cells and
acanthocytes.
Folate deficiency
 Found in: Fruits (e.g. citrus, melon, bananas),
leafy green vegetables.
 Causes include:
Malabsorption
Medications
Malignancy
 Hemodialysis
Diseases/conditions associated with rapid cell
turnover such as pregnancy, infancy,….
Vitamin B12 deficiency
 Found in : (meat, fish)
 The body stores large amounts of B12 therefore
decreased dietary intake rarely lead to deficiency
 Medications to decrease stomach acid can also
contribute to B12 deficiency (antacids)
 Vegetarians can also contribute to B12 deficiency
 In addition to causing anemia, B12 deficiency can lead
to a metabolic peripheral=neuropathy and
gastrointestinal disorders.
Diagnosis
1. Blood cell count:
•
•
•
•
macrocytic anemia ( MCV>100fl )
thrombocytopenia
leucopenia (granulocytopenia)
low reticulocyte count
2. Blood smear:
• macrocytosis , anisocytosis.
• hypersegmentation of granulocytes
Diagnosis
3. Laboratory features
hyperbilirubinemia
elevation of lactate dehrogenase (LDH)
serum iron concentration- normal or increased
4. Bone marrow smear
hypercellular
erythroid cell changes (megaloblasts, an abnormally large
cell with nuclear- cytoplasmic asynchrony)
myeloid cell changes (hypertsegmentation)
megakaryocytes are decreased and show abnormal
morphology
Hemolytic Anemia
Normocytic
Normochromic
Hemolytic Anemia
Congenital •
Membrane defects –
Hereditary spherocytosis •
Hereditary elliptocytosis •
Enzyme defects –
G6PD deficiency, PKD,…. •
Hemolytic Anemia
• Acquired
– Classified according to site of RBC destruction and/or whether
mediated by immune system:
•
•
•
•
Intravascular
Extravascular
Immune
Non-immune
– Causes: –
• Transfusion of incompatible blood
• Autoimmune
– Warm (IgG-mediated) ; most common
– Cold (IgM-mediated)
• Prosthetic valves
• TTP/HUS
• DIC
• Cancer
• Drugs
Haematological findings in HS
• Anaemia is usual.[Increased mean corpuscular hemoglobin
concentration (MCHC)]
• Reticulocytosis 5-20%
• Microspherocytes are seen in the blood film.
(densely staining with smaller diameters than
normal red cells).
Other investigations
• The classic finding is that the osmotic fragility
is increased.
• Autohaemolysis is increased and corrected by
glucose.
• Direct antiglobulin test is normal
G6PD deficiency
• G6PD functions to reduce nicotinamide
adenine dinucleotide phosphate (NADP)
while oxidizing glucose-6-phosphate.
• NADPH is needed for the production of
reduced glutathione (GSH) which is
important to defend the red cells against
oxidant stress.
Clinical features
• G6PD deficiency is usually asymptomatic.
• Neonatal jaundice.
• Acute haemolytic anaemia in response to
oxidant stress: drugs, fava beans or infections.
Laboratory diagnosis
• Between crises blood count is normal.
• The enzyme deficiency is detected by
– One of a number of screening tests or
– By direct enzyme assay on red cells.
• During the crisis, the blood film may show contracted
and fragmented cells, bite, blister cells, ………
• Enzyme assay may give a false normal level in the
phase of acute haemolysis.
• The blood film shows
irregularly contracted cells
[deep red arrows]
and sometimes hemighosts
[deep blue arrow] in which
all the hemoglobin appears
to have retracted to one
side of the erythrocyte
Polycythemia / Erythrocytosis
• Abnormal elevation of hemoglobin
– Rule out “relative” polcythemia caused by contraction of plasma volume,
e.g. dehydration
– Primary
• Polycythemia Vera
– RBC production independent of EPO
» EPO level is low / positive JAK-2 is diagnostic
– Uncommon
– May be associated with leukocytosis, thrombocytosis, splenomegaly
– Hyperviscosity
» Headache, vertigo, visual changes, mental confusion
– Risk of transformation into acute leukemia
– Treatment??
– Secondary
• RBC production in response to increased EPO production
– EPO level is usually high
• Very common
• Usual etiology is chronic hypoxia (COPD)
**……………. (250-500 ml) to maintain hct 45-50% and treat underlying problem
Reticulocytes
• Immature RBCs.
• Contain residual
ribosomal RNA.
• Reticulum stains
blue using a
supravital stain
(new methylene
blue).
• Counted and
expressed as % of
total red cells.
Reticulocyte Count
Retic % =
# retics per 100 RBCs
Corrected retic= % retics x pt. HCT
45
What are hemoglobinopathies?
• A group of inherited disorders characterized by
structural variations of the Hb molecule. They are
Disorders of globin synthesis rather than heme
synthesis.
• These may result from :
1. Synthesis of abnormal Hb
2. Reduced rate of synthesis of NORMAL α or β
globin chains
• Genetic defects of Hb are the most common
genetic disorders worldwide.
SICKLE CELL
ANAEMIA
Sickle cell disease is a group of
haemoglobin disorders, in which there is
inherence globin abnormality, caused by
substitution of valine for glutamic
acid in position 6 in the ß chain.
• Hb S is insoluble and forms crystals
when exposed to low oxygen tension.
• Deoxygenated Hb polymerizes into long
fibers which may block different areas
of the microcirculation or large vessels
causing infarcts of various organs.
Clinical features:
- Chronic haemolysis, leads to jaundice and
anemia.
- Vaso-occlusion of blood vessels leads to pain.
- Infarction and infections.
1. Low Hb.
2. Peripheral blood film shows, sickle cells,
target cells and howell-Jolly body appears.
3. Positive Sickling test (screening test).
4. Hb electrophoresis (confirmatory test) :
-Hb SS : 80 – 100%
- no Hb A
- Hb F : 5 – 15%
Howell-Jolly bodies
• These are basophilic
nuclear
remnants
(clusters of DNA) in
circulating erythrocytes.
• They
are
usually
observed in hemolytic
anemia,
following
splenectomy, and in
cases of splenic atrophy.
The Sickling Test
• This is a wet preparation.
• 5 drops of reagent (Sodium dithionite), are added
to 1 drop of anticoagulated blood on a slide. Cover
glass is put on and sealed with petrollium
jelly/parraffin wax mixture.
• The reagent is a reducing agent.
• In Hb SS, sickling occur immediately, while it may
take 1 hour in Hb S trait.
Hb S solubility Test
• This is done after the Hb electrophoresis to differentiate
between some hemoglobins that have the same
electrophoretic mobility. (Differentiate Hb D & Hb G from Hb
S)
• Only Hb S precipitate in the reduced state when placed in a
high molarity phosphate buffer (as it removes oxyegen from
test environment).
• 0.05 ml of blood is added to 1 ml of the buffer and mixed in
a test tube. Positive results : presence of Hb S : cloudy
solution . Negative results : other Hbs : clear solution .
Sicle cell trait
This is a benign condition, where there is
no anaemia and normal appearance of
RBC on the BF. Haematuria is the most
common symptom. Care must be taken
with anesthesia, pregnancy and at high
altitude.
THALASSAEMIA
*There are two
alpha genes on each of two chromosome 16
(four genes in the diploid state)
*Only 2 beta globin genes, one on each chromosome 11
**Excess alpha chains are unstable -precipitates in the cell which
bind to cell membrane, causing membrane damage
**Excess b chains
* High oxygen affinity – poor oxygen transporter
* unstable
Thalassaemias are a heterogeneous group of
genetic disorders, which results from a
reduced rate of œ (alpha) and ß (beta) chain
synthesis.
•
•
In alpha thalassaemia, there is no or little
alpha-chain syntheses.
In beta thalassaemia, there is no or little
beta-chain syntheses.
ALPHA THALASSEMIA
1-
Major alpha- thalassaemia or Hydrops fetalis or Hemoglobin
Barts : four genes deletion, leads to complete suppression in the
synthesis of alpha-chain. Alpha chain is important in formation
of hemoglobin F in neonate, so in this case the formation of this
haemoglobin which is important for fetal life will fail, leading to
death in uterus.
2- Three genes deletion: leads to moderate to sever microcytic
hypochromic anaemia, with splenomegaly. This is known as Hb
H disease.
3- Two genes deletion: alpha-thalassaemia trait or minor, associated
with mild anaemia.
4-One gene deletion: silent thalassemia usually asymptomatic.
Alpha-Thalassemia minor
*Two alpha genes either on same or opposite
chromosomes are missing
*Unaffected globin genes are able to
compensate for the affected genes
*Mild anemia – significant microcytosis
*Normal lifespan
*Hb. Electrophoresis is normal.
Normal Hemoglobin Electrophoresis
* Hgb F (N = < 1% after age 1 year)
* Hgb A2 (N = 2-3.5%)
*Hgb A1 (N=95.5-100%)
Causes:
deletion
0 deletion
One deletion
Two
deletions
Three
deletions
deletion of all
four a globin
genes
Type
genotype
Clinical
Normal /
Thal : +
heterozygous
- /
Thal trait: +
homozygous or
0 heterozygous
-/-
Silent carrier: mild
hypochromic microcytic
anemia
Minor: mild hypochromic
microcytic anemia
--/
Hb H
disease:0/+
double
heterozygous
Hb Bart’s; homozygous
--------
--/- variable severity, but less
severe than Beta Thal Major
--/--
Hydrops Fetalis:In Utero or
early neonatal death
complete absence of a globin
synthesis
BETA-THALASSEMIA
Classification:
1. ß- Thalassaemia major, very
sever.
2. Intermediate ß- thalassaemia
3. ß- Thalassaemia minor or trait.
Beta-thalassemia Major
1. Sever anaemia (2-3 g/dl)
2. Enlargement of liver and spleen.
3. Expansion of bones, leads to Bone
deformities.
The classification of Beta Thalassemias
Causes: one
point
mutation
0 mutation
Type
Normal
genotype Clinical
/
Minor point
mutation
Minor: Trait
0 heterozygous
Or
+ heterozygous
/0
/+
Minimal anemia; no treatment
indicated
Two
mutations
Intermedia
Double distinct mutation
0/+
severe heterozygote
Can be a spectrum; most often
do not require chronic
transfusions
Severe gene
mutations
Major
+ homozygous(double)
Or
0 homozygous (double)
+/+
0/0
Cooley’s Anemia
Homozygous minor point
mutation
Need careful observation and
intensive treatment
• Laboratory findings:
*Hemoglobin as low as 2-3 g/dl
*Markedly microcytic/hypochromic
*Marked anisocytosis and poikilocytosis
*Basophilic stippling and polychromasia
*Hemoglobin electrophoresis –90% Hb F and
increased Hb A2
*HPLC: confirmatory test
Beta-thalassemia intermedia
Of moderate severity (Hb 7-10 g/dl). The
patient may show bone deformity, enlarged
liver and spleen.
-This is usually symptomless, but mild anaemia may occur.
-Normal iron, ferritin, TIBC
-Prenatal counseling.
(25% risk rate if both partners carry beta thalassemia minor).
-Hb. Electrophoresis:
4-7 % Hgb A2
92-95% Hgb A1
2-6 % Hgb F

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